The Washington State Department of Agriculture (WSDA) has been conducting annual monitoring to evaluate pesticide concentrations in surface waters since 2003. Collecting data on the fate and transport of pesticides used in Washington State allows WSDA, the pesticide user community, U.S. EPA, NOAA Fisheries, U.S. Fish and Wildlife Service, and others to:

• Develop effective mitigation strategies to minimize offsite movement
• Identify opportunities for increased education and outreach to the user community
• Recommend best management practices
• Make informed management decisions that protect Endangered Species Act listed species (including salmon)
• Refine exposure estimates and model assumptions that are routinely used to estimate risk in risk assessments
• Support the continued uses of valuable pest management tools for agriculture

Field sampling is conducted at salmonid-bearing streams in selected watersheds from March through October by staff from Natural Resources and Agricultural Sciences. Samples at site visits are analyzed for an extensive list of insecticides, herbicides, fungicides, breakdown products, and even some pesticides that have been used historically but are no longer registered. Data is also gathered for total suspended solids, pH, dissolved oxygen, conductivity, continuous streamflow, continuous air temperature, and continuous water temperature at all site visits.

Surface Water Monitoring Program QAPP Addendum 7 [PDF 204 KB]

Surface Water Monitoring Program Initial QAPP [PDF 1654 KB]

Please visit the NRAS publications page to view additional supporting information.

The surface water monitoring for pesticides online dashboard displays locations for all of the monitoring sites from 2003 through 2018 and a summary of the monitoring results.

• 2021 Surface Water Monitoring Watershed Fact Sheets

  Ahtanum Creek [PDF 2.6 MB] Brender Creek [PDF 3.7 MB] Burnt Bridge Creek [PDF 1.9 MB] Dry Creek [PDF 7.9] Indian Slough [PDF 1.8 MB] Juanita Creek [PDF 1.6 MB] Kamiache Creek [PDF 2.5 MB] Lower Bertrand Creek [PDF 2.2 MB] Lower Big Ditch [PDF 1.6 MB]

  Marion Drain [PDF 2.1 MB] Mission Creek [PDF 1.8 MB] Stemilt Creek [PDF 2.2 MB] Snipes Creek [PDF 2.2 MB] Sulphur Creek [PDF 2.1 MB] Thorn Creek [PDF 2.7 MB] Touchet River [PDF 9.3 MB] Upper Bertrand Creek [PDF 2.2 MB] Upper Big Ditch [PDF 1.8 MB]

• 2021 Technical Report: Ambient Monitoring for Pesticides in Washington State Surface Water [PDF 7.6 MB]

Please visit the NRAS publications page to view previous reports and fact sheets.